Exercises in anatomy: cardiac isomerism

Area of Science:

• Cardiology
• Anatomy
• Medical Imaging

Background:

• Patients with complex cardiac malformations often have visceral heterotaxy.
• Current classification relies on splenic anatomy (asplenia/polysplenia), which is less accurate than bronchial morphology.
• Tracheobronchial tree isomerism is consistently observed in heterotaxy and correlates better with cardiac anatomy.

Purpose of the Study:

• To demonstrate isomeric features in hearts from patients with visceral heterotaxy.
• To highlight the role of atrial appendages in identifying cardiac isomerism.
• To emphasize the importance of bronchial isomerism as a guide for cardiac analysis.

Main Methods:

• Analysis of hearts from the Idriss archive at Lurie Children's Hospital.
• Demonstration of normal atrial appendage morphology and bronchial asymmetry.
• Illustration of isomeric atrial appendages and veno-atrial connections in heterotaxy cases.

Main Results:

• Atrial appendages are universally isomeric in heterotaxy, distinguishing right and left chambers.
• Bronchial isomerism correlates more accurately with cardiac anatomy than splenic anomalies.
• Failure to recognize isomeric appendages can lead to misdiagnosis of atrioventricular connections.

Conclusions:

• Isomeric atrial appendages, identified with guidance from bronchial isomerism, are key indicators in visceral heterotaxy.
• Accurate diagnosis requires a comprehensive segmental sequential analysis.
• Understanding isomerism is crucial for correctly diagnosing and managing complex congenital heart disease.